Electrosurgical system for use with non-stick coated electrodes

ABSTRACT

An electrosurgical system includes an electrosurgical instrument having an electrode with a polymeric dielectric coating; and an electrosurgical generator, which includes a power converter configured to generate RF energy; a sensor coupled to the power converter and configured to sense a parameter of the RF energy; and a controller coupled to the sensor and the power converter. The controller is configured to control the power converter to output an RF waveform to achieve conductor breakthrough through the polymeric dielectric coating. The controller is further configured to determine whether the conductor breakthrough occurred based on the parameter; and execute a treatment algorithm based on a determination of the conductor breakthrough.

BACKGROUND 1. Technical Field

The present disclosure relates to an electrosurgical generator for usewith electrosurgical tissue sealing instruments having a non-stickcoating disposed on one or more electrodes. More particularly, thepresent disclosure relates to a system and method of applyingelectrosurgical energy to overcome the insulative properties on thenon-stick coating.

2. Background of the Related Art

Electrosurgical forceps utilize mechanical clamping action along withelectrical energy to effect hemostasis on the clamped tissue. Theforceps (open, laparoscopic or endoscopic) include sealing plates whichapply energy to the clamped tissue. By controlling the intensity,frequency and duration of the energy applied through the sealing platesto the tissue, the surgeon can cut, coagulate, cauterize, and/or sealtissue.

In the past, efforts have been made to reduce the sticking of softtissue to the sealing plate during application of energy. In general,such efforts have envisioned non-stick surface coatings, such aspolytetrafluoroethylene (PTFE, commonly sold under the trademarkTEFLON®) for increasing the lubricity of the tool surface. However,these materials may interfere with the efficacy and efficiency ofhemostasis. Accordingly, there is a need for electrosurgical generatorsconfigured to operate with electrosurgical instruments having anon-stick coating disposed on one or more electrodes.

SUMMARY

Electrosurgical instruments described herein include at least one tissuesealing plate including a non-stick coating configured to reduce thesticking of soft tissue to the sealing plate during application ofenergy.

According to one embodiment of the present disclosure, anelectrosurgical system is provided. The electrosurgical system includesan electrosurgical instrument having an electrode with a polymericdielectric coating; and an electrosurgical generator, which includes apower converter configured to generate RF energy; a sensor coupled tothe power converter and configured to sense a parameter of the RFenergy; and a controller coupled to the sensor and the power converter.The controller is configured to control the power converter to output anRF waveform to achieve conductor breakthrough through the polymericdielectric coating. The controller is further configured to determinewhether the conductor breakthrough occurred based on the parameter; andexecute a treatment algorithm based on a determination of the conductorbreakthrough.

According to one aspect of the above embodiment, the controller isfurther configured to compare the parameter to a set thresholdindicative of the conductor breakthrough. The controller is furtherconfigured to control the power converter to output the RF waveform fora set period of time and to execute the treatment algorithm based on thedetermination of the conductor breakthrough occurring within the setperiod of time.

According to another aspect of the above embodiment, the parameter thatis measured is impedance and the controller is further configured tocompare the measured impedance to a set impedance threshold. Thecontroller is further configured to execute the treatment algorithm inresponse to the measured impedance being below the set impedancethreshold and to adjust a power setting of the treatment algorithm priorto the execution of the treatment algorithm in response to the measuredimpedance being above the set impedance threshold. The controller isfurther configured to adjust a power setting of the RF waveform inresponse to the measured impedance being above the set impedancethreshold.

According to a further aspect of the above embodiment, the parameterthat is measured is one of voltage or current and the controller isfurther configured to compare the measured voltage and/or current to aset voltage and/or current threshold.

According to another embodiment of the present disclosure, a method isprovided. The method includes electrically coupling an electrosurgicalinstrument to an electrosurgical generator. The electrosurgicalinstrument includes an electrode having a polymeric dielectric coating.The method further includes controlling a power converter of theelectrosurgical generator to output an RF waveform to achieve conductorbreakthrough through the polymeric dielectric coating and sensing atleast one parameter of the RF waveform at a sensor of theelectrosurgical generator. The method further includes determining at acontroller of the electrosurgical generator whether the conductorbreakthrough occurred based on the at least one parameter and executinga treatment algorithm at the controller based on a determination of theconductor breakthrough.

According to one aspect of the above embodiment, determining whether theconductor breakthrough occurred further includes comparing the at leastone parameter to a set threshold indicative of the conductorbreakthrough. The method further includes outputting the RF waveform fora set period of time. Further, the treatment algorithm is executed basedon the determination of the conductor breakthrough occurring within theset period of time.

According to another aspect of the above embodiment, the method furtherincludes measuring impedance; and comparing the measured impedance to aset impedance threshold. The method further includes executing thetreatment algorithm in response to the measured impedance being belowthe set impedance threshold. The method further includes adjusting apower setting of the treatment algorithm prior to the execution of thetreatment algorithm in response to the measured impedance being abovethe set impedance threshold. The method further includes adjusting apower setting of the RF waveform in response to the measured impedancebeing above the set impedance threshold.

According to another aspect of the above embodiment, the method furtherincludes measuring voltage and/or current and comparing the measuredvoltage and/or current to a set voltage and/or current threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentelectrosurgical tissue sealing instruments will become more apparent inlight of the following detailed description when taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a laparoscopic bipolar forceps inaccordance with an aspect of the present disclosure;

FIG. 2 is a perspective view of an open bipolar forceps according to anaspect of the present disclosure;

FIGS. 3A and 3B are exploded views of opposing jaw members according toan aspect of the present disclosure;

FIG. 4A is a front cross sectional view of a sealing plate according toan aspect of the present disclosure;

FIG. 4B is a front cross sectional view of a jaw member according to anaspect of the present disclosure;

FIG. 5 is a perspective view of an electrosurgical system according toan aspect of the present disclosure;

FIG. 6 is a front view of an electrosurgical generator of theelectrosurgical system of FIG. 5 according to an aspect of the presentdisclosure;

FIG. 7 is a schematic diagram of the electrosurgical generator accordingto an aspect of the present disclosure;

FIG. 8 is a flow chart of a method for applying a radio frequencywaveform to achieve conductor breakthrough through a dielectric coatingaccording to an aspect of the present disclosure;

FIG. 9 is a flow chart of a method for applying a radio frequencywaveform to achieve conductor breakthrough through a dielectric coatingaccording to another aspect of the present disclosure; and

FIG. 10 is a flow chart of a method for applying a radio frequencywaveform to achieve conductor breakthrough through a dielectric coatingaccording to a further aspect of the present disclosure.

DETAILED DESCRIPTION

Particular aspects of the present electrosurgical tissue sealinginstruments are described herein below with reference to theaccompanying drawings; however, it is to be understood that thedisclosed aspects are merely examples of the disclosure and may beembodied in various forms. Well-known functions or constructions are notdescribed in detail to avoid obscuring the present disclosure inunnecessary detail. Therefore, specific structural and functionaldetails disclosed herein are not to be interpreted as limiting, butmerely as a basis for the claims and as a representative basis forteaching one skilled in the art to variously employ the concepts of thepresent disclosure in virtually any appropriately detailed structure.

Like reference numerals may refer to similar or identical elementsthroughout the description of the figures. As shown in the drawings anddescribed throughout the following description, as is traditional whenreferring to relative positioning on a surgical instrument, the term“proximal” refers to the end of the apparatus which is closer to theuser and the term “distal” refers to the end of the apparatus which isfurther away from the user. The term “clinician” refers to any medicalprofessional (i.e., doctor, surgeon, nurse, or the like) performing amedical procedure involving the use of aspects described herein.

All numerical values and ranges disclosed above may vary by some amount.Whenever a numerical range with a lower limit and an upper limit isdisclosed, any number and any included range falling within the rangeare specifically disclosed. In particular, every range of values (of theform, “from about a to about b,” or, equivalently, “from approximately ato b,” or, equivalently, “from approximately a-b”) disclosed herein isto be understood to set forth every number and range encompassed withinthe broader range of values. Unless the meaning is clearly to thecontrary, all ranges set forth herein are deemed to be inclusive of theendpoints. Unless specifically stated or obvious from context, as usedherein, the term “about” when used in conjunction with a statednumerical value or range denotes somewhat more or somewhat less than thestated value or range, to within a range of ±10% of that stated value orrange.

As described in more detail below with reference to the accompanyingfigures, the present disclosure is directed to electrosurgicalinstruments having a non-stick coating disposed on one or morecomponents (e.g., tissue sealing plates, jaw members, electrical leads,insulators etc.) The thickness of the non-stick coating is carefullycontrolled, allowing for desired electrical performance while providingtissue sticking reduction during tissue sealing.

Any material capable of providing the desired functionality (namely,reduction of tissue sticking while simultaneously maintaining sufficientelectrical transmission to permit tissue sealing) may be used as thenon-stick coating, provided it has adequate biocompatibility. Thematerial may be porous to allow for electrical transmission. Among suchmaterials are silicone and silicone resins that can be applied using aplasma deposition process to precisely control thickness, and canwithstand the heat generated during tissue sealing. Silicone resinssuitable for the non-stick coating include, but are not limited to,polydimethyl siloxanes, polyester-modified methylphenyl polysiloxanes,such as polymethylsilane and polymethylsiloxane, and hydroxyl functionalsilicone resins. In some embodiments, the non-stick coating is made froma composition including a siloxane, which may includehexamethyldisiloxane, tetramethylsilane, hexamethyldisilazane, orcombinations thereof.

In some embodiments, the non-stick coating is a polydimethylsiloxanecoating formed by plasma-enhanced chemical vapor deposition (“PECVD”) ofhexamethyldisiloxane (“HMDSO”). Advantageously, the polydimethylsiloxanecoating operates to reduce the sticking of tissue to the sealing platesand/or the entire jaw member. Additionally, the polydimethylsiloxanecoating may operate to reduce the pitting of the sealing plates and mayprovide durability against electrical and/or mechanical degradation ofthe sealing plates and the jaw members, as a whole.

In some embodiments, opposing jaw members of an electrosurgical vesselsealing instrument (see FIGS. 1 and 2) include electrically conductivetissue sealing plates on which the non-stick coating is directlydeposited. The application of the non-stick coating may be accomplishedusing any system and process capable of precisely controlling thethickness of the coating. In some embodiments, HMDSO is deposited on thesealing plates using plasma enhanced chemical vapor deposition (PECVD)or other suitable methods such as atmospheric pressure plasma enhancedchemical vapor deposition (AP-PECVD). For example, the application ofthe polydimethylsiloxane coating may be accomplished using a system andprocess that includes a plasma device coupled to a power source, asource of liquid and/or gas ionizable media (e.g., oxygen), a pump, anda vacuum chamber. One such illustrative system and process is describedin commonly-owned U.S. Patent Application Publication No. US2013/0116682, the entire contents of which are incorporated herein byreference. The power source may include any suitable components fordelivering power or matching impedance to the plasma device. Moreparticularly, the power source may be any radio frequency generator orother suitable power source capable of producing electrical power toignite and sustain the ionizable media to generate a plasma effluent.

The thickness of the non-stick coating affects the non-stick performanceof the sealing plates and may affect the tissue sealing performance ofthe sealing plates as well. For example, if the non-stick coating is toothick, the tissue sealing performance of the sealing plates may benegatively affected. More specifically, a non-stick coating above aparticular thickness (e.g., greater than about 200 nm) may create auniform dielectric barrier or surface impedance on the sealing plates,which may negatively impact the effectiveness of tissue sensingalgorithms employed by an electrosurgical generator that controls thedelivery of electrosurgical energy to the vessel sealing instrumentbased on sensed tissue parameters (e.g., impedance, temperature, etc.)generated by the application of electrosurgical energy to the tissue viathe sealing plates. If the applied non-stick coating is too thin (e.g.,less than about 20 nm), the non-stick coating may not provide adequatetissue sticking reduction.

Embodiments of the present disclosure provide for disposing a non-stickcoating on components of a vessel sealing instrument (e.g., sealingplates, jaw members, electrical leads, insulators, etc.) at a particularthickness or within a particular range of thicknesses such that thenon-stick coating provides adequate tissue sticking reduction duringtissue sealing without negatively impacting tissue sealing performanceof the vessel sealing instrument.

In some embodiments, a polydimethylsiloxane coating may be applied to aportion of the electrosurgical device at a thickness from about 20 nm toabout 200 nm, in embodiments, the coating may be from about 25 nm toabout 120 nm, and in further embodiments, from about 35 nm to about 85nm. In a particular embodiment, the non-stick coating may be about 60 nmthick. In some embodiments, the thickness of the non-stick coating mayvary such that the non-stick coating has a substantially non-uniformthickness. For example, a first portion of the non-stick coating may beabout 60 nm thick and any one or more other portions of the non-stickcoating may have a thickness other than about 60 nm but within the rangeof about 20 nm to about 200 nm, in embodiments within the range of fromabout 25 nm to about 120 nm, and in further embodiments, from about 35nm to about 85 nm. In other embodiments, the non-stick coating has asubstantially uniform thickness. Without wishing to be bound by anyparticular theory, it is believed that polydimethylsiloxane coatings inthe foregoing range do not provide a complete surface seal, and that itis the lack of a complete uniform seal over the surface at thesecontrolled thicknesses that allows the electrical algorithms of certainelectrosurgical generators to perform properly. One such electrosurgicalgenerator employing a tissue sensing algorithm is described in U.S. Pat.No. 9,603,752, the entire contents of which are incorporated herein bythis reference. Those skilled in the art reviewing the presentdisclosure will readily envision other electrosurgical generatorsemploying other algorithms.

In some embodiments, the thickness of the non-stick coating is about0.01% of the thickness of the sealing plate.

Turning now to FIG. 1, an instrument generally identified as forceps 10is for use with various surgical procedures and includes a housing 20, ahandle assembly 30, a rotating assembly 80, a trigger assembly 70, andan end effector 130 that mutually cooperate to grasp, seal, and dividetubular vessels and vascular tissues. Forceps 10 includes a shaft 12extending from a distal end of the housing 20. The shaft 12 has a distalend 16 configured to mechanically engage the end effector 130 and aproximal end 14 that mechanically engages the housing 20.

The end effector 130 includes opposing jaw members 110 and 120, whichcooperate to effectively grasp tissue for sealing purposes. Both jawmembers 110 and 120 pivot relative to one another about a pivot pin (notshown). Alternatively, the forceps 10 may include a jaw member 110movable relative to a stationary jaw member 120, and vice versa. The jawmembers 110 and 120 may be curved to facilitate manipulation of tissueand to provide better “line-of-sight” for accessing targeted tissues. Asensor 140 may be disposed on or proximate to at least one of the jawmembers 110 and 120 for sensing tissue parameters (e.g., temperature,impedance, etc.) generated by the application of electrosurgical energyto tissue via the jaw members 110 and 120. The sensor 140 may include atemperature sensor, tissue hydration sensor, impedance sensor, opticalclarity sensor, jaw gap sensor, strain and/or force sensor, or the like.Through a cable (not shown) coupling the forceps 10 to anelectrosurgical generator (not shown), sensed tissue parameters may betransmitted as data to the electrosurgical generator having suitabledata processing components (e.g., microcontroller, memory, sensorcircuitry, etc.) for controlling delivery of electrosurgical energy tothe forceps 10 based on data received from the sensor 140.

Examples of forceps are shown and described in U.S. Patent ApplicationPublication No. 2013/0296922 and U.S. Pat. No. 9,655,673, the entirecontents of each of which are incorporated herein by reference.

With regard to FIG. 2, an open forceps 100 for use with various surgicalprocedures is shown. The forceps 100 includes a pair of opposing shafts116 and 126 having an end effector 200 disposed at a distal end of theshafts 116, 126. The end effector 200 includes pair of opposing jawmembers 210 and 220 that are connected about a pivot member 150 and thatare movable relative to one another to grasp tissue. Each shaft 116 and126 includes a handle 118 and 128, respectively, to facilitate movementof the shafts 116 and 126 relative to one another to pivot the jawmembers 210 and 220 between an open position, wherein the jaw members210 and 220 are disposed in spaced relation relative to one another, anda closed position, wherein the jaw members 210 and 220 cooperate tograsp tissue there between. Similar to the forceps 10 shown in FIG. 1, asensor 240 may be disposed on or proximate to at least one of the jawmembers 210 and 220 of the forceps 100 for sensing tissue parameters(e.g., temperature, impedance, etc.) generated by the application ofelectrosurgical energy to tissue via the jaw members 210 and 220. Thesensor 240 may include a temperature sensor, tissue hydration sensor,impedance sensor, optical clarity sensor, or the like. Through a cable(not shown) coupling the forceps 100 to an electrosurgical generator(not shown), sensed tissue parameters may be transmitted as data to theelectrosurgical generator having suitable data processing components(e.g., microcontroller, memory, sensor circuitry, etc.) for controllingdelivery of electrosurgical energy to the forceps 100 based on datareceived from the sensor 240.

FIGS. 3A and 3B show perspective views of the jaw members 310 and 320,respectively, according to an embodiment of the present disclosure. Thejaw members 310 and 320 may be utilized with the endoscopic forceps 10(FIG. 1) or the open forceps 100 (FIG. 2) and operate similarly asdescribed above with respect to the jaw members 110 and 120 (FIG. 1) andthe jaw members 210 and 220 (FIG. 2). Each of the jaw members 310 and320 include: sealing plates 312 and 322, respectively; electrical leads325 a and 325 b, respectively; and support bases 319 and 329 that extenddistally from flanges 313 and 323, respectively.

Each of the sealing plates 312 and 322 include an underside 328 a and328 b, respectively, that may include a respective electricallyinsulative layer 330 a and 330 b bonded thereto or otherwise disposedthereon. The electrically insulative layers 330 a and 330 b operate toelectrically insulate the sealing plates 312 and 322, respectively, fromthe support bases 319 and 329, respectively. Further, the electricallyinsulative layers 330 a and 330 b operate to prevent or slow the onsetof corrosion of the sealing plates 312 and 322, respectively, at leaston the undersides 328 a, 328 b thereof. In one embodiment, theelectrically insulative layers 330 a and 330 b may be formed frompolyimide. However, in other embodiments, any suitable electricallyinsulative material may be utilized, such as polycarbonate,polyethylene, etc.

Additionally, each of the jaw members 310 and 320 include an outersurface 311 a and 311 b, respectively, that includes a non-stick (e.g.,polydimethylsiloxane) coating 400 disposed thereon. The non-stickcoating 400 may be disposed on selective portions of either of the jawmembers 310 and 320, or may be disposed on the entire outer surfaces 311a and 311 b. In some embodiments, the non-stick coating 400 is disposedon a tissue-engaging surface 317 a and 317 b of the sealing plates 312and 322, respectively. The non-stick coating 400 operates to reduce thesticking of tissue to the sealing plates 312 and 322, the jaw members310 and 320, the electrical leads 325 a and 325 b, and/or thesurrounding insulating material.

The support bases 319 and 329 are configured to support the sealingplates 312 and 322 thereon. The sealing plates 312 and 322 may beaffixed atop the support bases 319 and 329, respectively, by anysuitable method including but not limited to snap-fitting, overmolding,stamping, ultrasonic welding, laser welding, etc. The support bases 319and 329 and the sealing plates 312 and 322 are at least partiallyencapsulated by insulative housings 316 and 326, respectively, by way ofan overmolding process to secure sealing plates 312 and 322 to supportbases 319 and 329, respectively. The sealing plates 312 and 322 arecoupled to electrical leads 325 a and 325 b, respectively, via anysuitable method (e.g., ultrasonic welding, crimping, soldering, etc.).The electrical leads 325 a and 325 b serve to deliver electrosurgicalenergy (e.g., from an electrosurgical energy generator) to the sealingplates 312 and 322, respectively. More specifically, electrical lead 325a supplies a first electrical potential to sealing plate 312 andelectrical lead 325 b supplies a second electrical potential to opposingsealing plate 322.

Jaw member 320 (and/or jaw member 310) may also include a series of stopmembers 390 disposed on the tissue-engaging surface 311 b of the sealingplate 322 to facilitate gripping and manipulation of tissue and todefine a gap between the jaw members 310 and 320 during sealing andcutting of tissue. The series of stop members 390 may be disposed (e.g.,formed, deposited, sprayed, affixed, coupled, etc.) onto the sealingplate 322 during manufacturing. Some or all of the stop members 390 maybe coated with the non-stick coating 400 or, alternatively, may bedisposed on top of the non-stick coating 400.

The sealing plates 312 and 322 may include longitudinal knife slots 315a and 315 b, respectively, defined there through and configured toreceive a knife blade (not shown) that reciprocates through the knifeslots 315 a and 315 b to cut tissue. The electrically insulative layers330 a and 330 b disposed on the respective undersides 328 a and 328 b ofsealing plates 312 and 322, respectively, allow for various bladeconfigurations such as, for example, T-shaped blades or I-shaped bladesthat may contact the underside of the sealing plate (and/or insulatinglayer) during reciprocation through knife slots 315 a, 315 b. That is,the electrically insulative layers 330 a, 330 b operate to protect boththe knife blade and the undersides 328 a and 328 b of the sealing plates312 and 322, respectively, from damage or wearing. Further, in theinstance that an electrically conductive knife blade is utilized (e.g.,for electric tissue cutting), the electrically insulative layers 330 a,330 b help to electrically insulate the sealing plates 312, 322 from theelectrically conductive knife blade.

Turning now to FIG. 4A, a front cross sectional view of sealing plate312 is shown and will be described. Sealing plate 312 has a stainlesssteel layer 317, a non-stick coating 400, and, optionally, anelectrically insulative layer 330 a disposed on the underside 328 b ofthe stainless steel layer 317. The non-stick coating 400 may be appliedto at least the outer surface 311 a of the stainless steel layer 317.Bonding electrically insulative layer 330 a to stainless steel layer 317may be accomplished by any suitable method including, but not limitedto, applying adhesive between electrically insulative layer 330 a andstainless steel layer 317, using heat treatment to bond electricallyinsulative layer 330 a to stainless steel layer 317, and/or anycombinations thereof. The optional electrically insulative layer 330 amay have a thickness ranging from about 0.0005 inches to about 0.01inches.

The non-stick coating 400 may be discontinuous or continuous. In someembodiments, the discontinuity or continuity of the non-stick coating400 may depend on the thickness of the non-stick coating 400. In someembodiments, the non-stick coating may be continuous over the entiresealing plate 312, thereby hermetically sealing the sealing plate 312.In some embodiments, the non-stick coating may be discontinuous over theentire sealing plate 312. The discontinuous non-stick coating may beapplied intermittently on the sealing plate 312 using a suitablediscontinuous-coating or patch-coating process. The patchiness of thediscontinuous non-stick coating may allow the thickness of thediscontinuous non-stick coating to be increased relative to a continuousnon-stick coating while maintaining adequate non-stick performance andtissue sealing performance.

In some embodiments, the sealing plate 312 may be formed by bonding asheet of electrically insulative material to a sheet of stainless steeland coating the sheet of stainless steel with a non-stick coating. Oncethe two materials are bonded together, and the stainless steel sheet iscoated with the non-stick coating 400, sealing plate 312 may be formedby stamping, machining, or any other suitable method used to form asealing plate.

In some embodiments, the sealing plate 312 may first be formed bystamping, machining, or any other suitable method used to form a sealingplate. Once the sealing plate 312 is formed, the non-stick coating 400is applied to the sealing plate 312 prior to assembling jaw member 310.Once the sealing plate 312 is coated with the non-stick coating 400, thesealing plate 312 may be affixed atop the support base 319, secured tothe support base 319 via the insulative housing 316, and coupled to theelectrical lead 325 a as described above with respect to FIG. 3A to formthe jaw member 310. Optionally, once the jaw member 310 is formed, anon-stick coating may be applied to the other components of the jawmember 310 (e.g., the support base 319, the insulative housing 316, theelectrical lead 325 a, etc.). In some embodiments, a non-stick coatingmay be applied to other components of forceps 10 (FIG. 1) or forceps 100(FIG. 2) to reduce frictional sticking associated with operation ofthese devices. For example, a non-stick coating may be applied to theshaft 12 of forceps 10, to the pivot member 150 and opposing shafts 116and 126 of forceps 100, and/or to a knife (not shown) used with eitherof forceps 10 or forceps 100.

Turning now to FIG. 4B, a front cross sectional view of jaw member 310is shown and will be described. Jaw member 310 includes sealing plate312 having a stainless steel layer 317 and, optionally, an electricallyinsulative layer 330 a. Sealing plate 312 is affixed to support base 319via any suitable process. Additionally, with sealing plate 312 securedto support base 319, the combined sealing plate 312 and support base 319is secured to insulative housing 316 via any suitable process. Anon-stick coating 400 is applied to the outer surface 311 a of theassembled sealing plate 312, the support base 319, the insulativehousing 316, and, optionally the electrical lead 325 a (FIG. 3A). Insome embodiments it may be useful to partially coat the outer surface311 a of the jaw member 310 or include thicker layers of the non-stickcoating 400 on different portions of the outer surface 311 a of the jawmember 310.

Additionally or alternatively, in some embodiments, the sealing plate312 may be coated with the non-stick coating 400 in the manner describedabove with respect to FIG. 4A and the outer surface 311 a of the jawmember 310 may also be coated with the non-stick coating 400.

Once the non-stick coating 400 is disposed on the sealing plates 312 and322 and/or the jaw member 310, which may be assembled with an opposingjaw member (e.g., pivotably coupled) to form an end effector (e.g., endeffector 130 or end effector 200). In some embodiments, the non-stickcoating 400 may be disposed on the sealing plates 312 and 322 and/or thejaw member 310 subsequent to assembly of the end effector.

In some embodiments, a polydimethylsiloxane coating at theabove-described thickness or within the above-described range ofthicknesses may be combined with one or more additional coatings. Forexample, the one or more coatings may be disposed directly on thestainless steel layer of the sealing plate prior to thepolydimethylsiloxane coating being deposited such that thepolydimethylsiloxane coating is disposed directly on the one or morecoatings and not directly on the stainless steel layer of the sealingplate. U.S. Publication No. 2017/0119457 describes a vessel sealinginstrument having sealing plates with a HMDSO-based coating disposedover a chromium nitride (“CrN”) coating.

It is envisioned that any suitable chemical vapor deposition or plasmavacuum system may be used to perform the method, such as the systemdisclosed in U.S. Pat. No. 8,187,484, the entire contents of which isincorporated by reference herein. The non-stick coating 400 may beapplied using the method disclosed in U.S. patent application Ser. No.16/059,279, the entire contents of which is incorporated by referenceherein.

FIG. 5 is a perspective view of the components of one illustrativeembodiment of an electrosurgical system 610 according to the presentdisclosure. The system 610 may include an electrosurgical generator 700configured to couple to the forceps 10 (FIG. 1), forceps 100 (FIG. 2),or any other suitable electrosurgical instrument. One of the jaw members110 or 120 of the forceps 10 acts as an active electrode with the otherjaw member being a return electrode. Electrosurgical alternating RFcurrent is supplied to the active electrode of the forceps 10 by agenerator 700 via a supply line 624 that is connected to an activeterminal 730 (FIG. 5) of the generator 700. The alternating RF currentis returned to the generator 700 from the return electrode via a returnline 628 at a return terminal 632 (FIG. 5) of the generator 700. Thesupply line 624 and the return line 628 may be enclosed in a cable 638

The forceps 10 may be coupled to the generator 700 at a port havingconnections to the active and return terminals 730 and 732 (e.g., pins)via a plug (not shown) disposed at the end of the cable 638, wherein theplug includes contacts from the supply and return lines 624, 628 asdescribed in more detail below.

With reference to FIG. 6, a front face 740 of the generator 700 isshown. The generator 700 may include a plurality of ports 750-762 toaccommodate various types of electrosurgical instruments (e.g.,monopolar electrosurgical instrument, forceps 10, forceps 100, etc.).

The generator 700 includes a user interface 741 having one or moredisplay screens 742, 744, 746 for providing the user with variety ofoutput information (e.g., intensity settings, treatment completeindicators, etc.). Each of the screens 742, 744, 746 is associated witha corresponding port 750-762. The generator 700 includes suitable inputcontrols (e.g., buttons, activators, switches, touch screen, etc.) forcontrolling the generator 700. The screens 742, 744, 746 are alsoconfigured as touch screens that display a corresponding menu for theinstruments (e.g., forceps 10). The user then adjusts inputs by simplytouching corresponding menu options.

Screen 642 controls monopolar output and the devices connected to theports 750 and 752. Port 750 is configured to couple to a monopolarelectrosurgical instrument and port 752 is configured to couple to afoot switch (not shown). The foot switch may be used to provide foradditional inputs (e.g., replicating inputs of the generator 700).Screen 744 controls monopolar and bipolar output and the devicesconnected to the ports 756 and 758. Port 756 is configured to couple toother monopolar instruments. Port 758 is configured to couple to abipolar instrument (not shown).

Screen 746 controls the forceps 10 that may be plugged into one of theports 760 and 762, respectively. The generator 700 outputs energythrough the ports 760 and 762 suitable for sealing tissue grasped by theforceps 10. In particular, screen 746 outputs a user interface thatallows the user to input a user-defined intensity setting for each ofthe ports 760 and 762. The user-defined setting may be any setting thatallows the user to adjust one or more energy delivery parameters, suchas power, current, voltage, energy, etc. or sealing parameters, such asenergy rate limiters, sealing duration, etc. The user-defined setting istransmitted to a controller 724 (FIG. 7) where the setting may be savedin memory. In embodiments, the intensity setting may be a number scale,such as for example, from one to ten or one to five. In embodiments, theintensity setting may be associated with an output curve of thegenerator 700. The intensity settings may be specific for each forceps10 being utilized, such that various instruments provide the user with aspecific intensity scale corresponding to the forceps 10. The active andreturn terminals 730 and 732 (FIG. 7) may be coupled to any of thedesired ports 750-762.

With continued reference to FIG. 6, each of the ports 750-762 mayinclude a reader, such as an optical reader or a radio frequencyinterrogator, configured to communicate with the forceps 10 to extractdata pertaining to the forceps 10. Such data may be encoded in abarcode, an RFID tag, computer-readable storage, or any other datastorage medium 640, which may be disposed on the forceps 10 or any ofits components, such as the cable 638. In embodiments, the data mayinclude whether the forceps 10 includes coated or uncoated jaw members110 and 120. In further embodiments, the data may also includeproperties of the coating, such as its thickness, dielectric properties,current and voltage limits, temperature limits, and the like.

FIG. 7 shows a schematic block diagram of the generator 700, whichincludes a controller 724, a power supply 727, and a power converter728. The power supply 727 may be a high voltage, DC power supplyconnected to an AC source (e.g., line voltage) and provides highvoltage, DC power to the power converter 728, which then converts highvoltage, DC power into RF energy and delivers the energy to the activeterminal 730. The energy is returned thereto via the return terminal732. The active and return terminals 730 and 732 are coupled to thepower converter 728 through an isolation transformer 729.

The power converter 728 is configured to operate in a plurality ofmodes, during which the generator 700 outputs corresponding waveformshaving specific duty cycles, peak voltages, crest factors, etc. It isenvisioned that in other embodiments, the generator 700 may be based onother types of suitable power supply topologies. Power converter 728 maybe a resonant RF amplifier or a non-resonant RF amplifier, as shown. Anon-resonant RF amplifier, as used herein, denotes an amplifier lackingany tuning components, i.e., inductors, capacitors, etc., disposedbetween the power converter and a load “Z,” e.g., tissue coupled throughforceps 10.

The controller 724 includes a processor (not shown) operably connectedto a memory (not shown), which may include one or more of volatile,non-volatile, magnetic, optical, or electrical media, such as read-onlymemory (ROM), random access memory (RAM), electrically-erasableprogrammable ROM (EEPROM), non-volatile RAM (NVRAM), or flash memory.The processor may be any suitable processor (e.g., control circuit)adapted to perform the operations, calculations, and/or set ofinstructions described in the present disclosure including, but notlimited to, a hardware processor, a field programmable gate array(FPGA), a digital signal processor (DSP), a central processing unit(CPU), a microprocessor, and combinations thereof. Those skilled in theart will appreciate that the processor may be substituted for by anylogic control circuit adapted to perform the calculations and/or executea set of instructions described herein.

The controller 724 includes an output port that is operably connected tothe power supply 727 and/or power converter 728 allowing the processorto control the output of the generator 700 according to either openand/or closed control loop schemes. A closed loop control scheme is afeedback control loop, in which a plurality of sensors measure a varietyof tissue and energy properties (e.g., tissue impedance, tissuetemperature, output power, current and/or voltage, etc.), and providefeedback to the controller 724. The controller 724 then controls thepower supply 727 and/or power converter 728, which adjusts the DC and/orpower supply, respectively.

The generator 700 according to the present disclosure may also include aplurality of sensors (not shown). The sensors may be coupled to thepower supply 727 and/or power converter 728 and may be configured tosense properties of DC current supplied to the power converter 728and/or RF energy outputted by the power converter 728, respectively. Thecontroller 724 also receives input signals from the input controls ofthe generator 700 and/or forceps 10. The controller 724 utilizes theinput signals to adjust power outputted by the generator 700 and/orperforms other control functions thereon.

Power converter 728 includes a plurality of switching elements 728 a-728d arranged in an H-bridge topology. In embodiments, power converter 728may be configured according to any suitable topology including, but notlimited to, half-bridge, full-bridge, push-pull, and the like. Suitableswitching elements include voltage-controlled devices such astransistors, field-effect transistors (FETs), combinations thereof, andthe like. In embodiments, the FETs may be formed from gallium nitride,aluminum nitride, boron nitride, silicon carbide, or any other suitablewide bandgap materials. In further embodiments, the FETs may be anysuitable FETs, such as conventional silicon FETs.

The controller 724 is in communication with both power supply 727 andpower converter 728. Controller 724 is configured to output controlsignals, which may be a pulse-width modulated (“PWM”) signal, toswitching elements 728 a-728 d as described in further detail inco-pending application published as U.S. Patent Application PublicationNo. 2014/0254221, the entire contents of which are incorporated byreference herein. In particular, controller 724 is configured tomodulate a control signal d₁ supplied to power supply 727 and controlsignal d₂ supplied to switching elements 728 a-728 d of power converter728. Additionally, controller 724 is configured to calculate powercharacteristics of generator 700, and control generator 700 based atleast in part on the measured power characteristics.

The controller 724 is configured to execute one or more vessel sealingalgorithms, which control the output of the generator 700 to treattissue (e.g., seal vessels). Exemplary algorithms are disclosed incommonly-owned U.S. Pat. No. 8,147,485 and U.S. Patent ApplicationPublication No. 2016/0045248, the entire disclosures of all of which areincorporated by reference herein.

Algorithms according to the present disclosure may be embodied assoftware instructions executable by the controller 724. In embodiments,an algorithm may be an impedance-based energy delivery algorithm inwhich energy is delivered by the generator 700 to the tissue until apredetermined impedance threshold is met or energy is otherwisedelivered based on measured tissue impedance. In further embodiments,the sealing algorithm may include configurable parameters, which may bea value settable manually by the user or automatically by the controller724 during or prior to execution of the sealing algorithms. Suitableconfigurable parameters include threshold values, such as completionimpedance, starting impedance, and offset impedance; intensity setting,such as a current setting, and a voltage setting; and duration setting,such as maximum time of energy application. In embodiments, otherparameters of the algorithms may also be adjusted, such as theparameters of algorithms disclosed in U.S. Pat. No. 8,147,485 and U.S.Patent Application Publication No. 2016/0045248, which are incorporatedby reference as stated above.

In embodiments, the non-stick coating 400 of the jaw members 110 and 120may be too thick and thus, too insulating, such that the measuredimpedance between the jaw members 110 and 120 would be too high for thegenerator 700 to output RF energy to treat tissue, such as seal vessels.The present disclosure provides for a plurality of algorithms executableby the controller 724, which are configured to apply a sufficient amountof energy to the jaw members 110 and 120 to achieve conductorbreakthrough in order to overcome excessive insulation of the non-stickcoating 400 in situations, such as when the non-stick coating 400 is toothick.

The present disclosure provides for pre-treatment algorithms embodied assoftware instructions, which when executable by the controller 724,which controls the power converter 728 to output an RF waveform forovercoming excessing insulation of the non-stick coating 400 and achieveconductor breakthrough. The generator 700 monitors one or moreparameters that are indicative of conductor breakthrough. Once thecontroller 724 determines that conductor breakthrough has occurred, thecontroller 724 proceeds to execute a tissue treatment algorithm. If theconductor breakthrough is not achieved, the controller 724 prevents thegenerator 700 from outputting energy.

With reference to FIG. 8, a pre-treatment algorithm for achievingconductor breakthrough in jaw members 110 and 120 or any otherelectrodes having the non-stick coating 400 is embodied as a flow chart800. Initially, the controller 724 signals the power converter 728 tooutput an RF waveform. The RF waveform may be a 100% duty cyclecontinuous waveform having maximum power of about 300 Watts, maximumcurrent of about 3 Amps, and maximum voltage of about 200 Volts. Infurther embodiments, the RF waveform may be a pulsed waveform having aduty cycle from about 25% to about 90%. The RF waveform is applied for aset period of time, which may be from about 50 msec to about 1 sec, andin embodiments, may be from about 100 msec to about 200 msec. Thecontroller 724 continuously receives measured impedance from one or moresensors (not shown) of the generator 700 and compares the measuredimpedance to a set impedance that is indicative of achieving conductorbreakthrough of the non-stick coating 400. The set impedance may besettable by the user or automatically by the generator 700 based on thetype of forceps 10 that is connected to the generator 700.

If the measured impedance drops below the set impedance, then thecontroller 724 proceeds to execute a treatment algorithm such as sealingalgorithms disclosed in U.S. Pat. No. 8,147,485 and U.S. PatentApplication Publication No. 2016/0045248, which are incorporated byreference above. If the impedance is above the set threshold, then thegenerator 700 continues to apply the RF waveform until a predeterminedtime limit is reached.

In embodiments, the threshold for switching to the treatment algorithmmay be any other parameter, such as voltage or current. With respect toother parameters the threshold is selected that is also indicative ofincreasing conductivity of the jaw members 110 and 120. Increasingconductivity corresponds to achieving conductor breakthrough. Thus, inembodiments where current and/or voltage is used as a parameter, thecontroller 724 compares the measured current and/or voltage to a setcurrent and/or voltage threshold to determine if the measured currentand/or voltage is below the set current threshold. Once the measuredcurrent and/or voltage exceeds the set current threshold, then thecontroller 724 proceeds to execute the treatment algorithm. Similarly tothe impedance being used as a parameter, the generator 700 continues toapply the RF waveform until the set time period expires.

The controller 724 maintains a timer for the application of the RFwaveform and compares the measured time of the timer to the set timeperiod. In embodiments, the timer may be maintained by any othercontroller within or outside the generator 700. If the timer has not yetexpired and the impedance does not drop below the set threshold (or ifcurrent and/or voltage does not exceed the set threshold), the generator700 continues to apply the RF waveform until set time period expires. Ifthe set time period expires without the measured impedance droppingbelow the set threshold, or without the measured current and/or voltageexceeding the set threshold, then the pre-treatment algorithm instructsthe generator 700 to issue a retry alert, such as instructing the userto re-grasp the tissue with the jaw members 110 and 120.

With reference to FIG. 9, another embodiment of a pre-treatmentalgorithm for achieving conductor breakthrough in the non-stick coating400 is shown as a flow chart 900. Initially, the controller 724 signalsthe power converter 728 to output the RF waveform, which may be the sameas the RF waveform of the algorithm of the flow chart 800. The RFwaveform may be applied for a period of time, which may be from about 1msec to about 1 sec, and in embodiments, may be from about 100 msec toabout 200 msec. The controller 724 continuously receives measuredimpedance from sensors of the generator 700 and compares the measuredimpedance to the set impedance that is indicative of achieving conductorbreakthrough of the non-stick coating 400. In embodiments, thecontroller 724 may sample the measured impedance at a predeterminedrate. The set impedance may be settable by the user or automatically bythe generator 700 based on the type of forceps 10 connected to thegenerator 700. Similarly to the algorithm of the flow chart 800, themeasured parameter and threshold may be voltage and/or current.

If the measured impedance drops below the set impedance or if themeasured parameter is voltage and/or current and exceeds the setthreshold, then the controller 724 proceeds to execute the treatmentalgorithm such as sealing algorithms disclosed in U.S. Pat. No.8,147,485 and U.S. Patent Application Publication No. 2016/0045248,which are incorporated by reference above. If the impedance is above theset threshold, then the generator 700 executes the treatment algorithm,but with an adjustment.

In embodiments, the treatment algorithm may include a plurality of powersettings corresponding to the power of the treatment effect. Thus, a lowsetting, e.g., setting of 1, corresponds to the lowest power setting,and a high power setting, e.g., setting of 5, corresponds to the highestpower setting. The power setting may be implemented in the algorithm byassociating a power setting value with one or more adjustable parameterswithin the algorithm. In embodiments, adjustable parameters of thealgorithm may include a current setting and a voltage setting at whichthe algorithm, when executed by the controller 724 outputs a treatmentRF waveform. In embodiments, the controller 724 may store a look-uptable of power setting values and one or more corresponding adjustableparameters, such that when the power setting is selected, the controller724 selects corresponding parameters.

The adjustment to the treatment algorithm includes automaticallyselecting a suitable power setting based on the comparison of themeasured impedance or other parameter to the set threshold. If theimpedance is above the set threshold, then the generator 700 executesthe treatment algorithm at a higher power setting.

In embodiments, the controller 724 is configured to execute thetreatment algorithm at a higher power setting if the impedance is abovethe set threshold. The amount of the power increase is correlated to theamount of the difference between the measured impedance or otherparameter and the set threshold. In further embodiments, the algorithmmay adjust the power setting of the treatment algorithm if the measuredimpedance is also below the set threshold. Thus, if the measuredimpedance is substantially equal (±5%) to the set threshold, then thecontroller 724 proceeds to execute the pre-treatment algorithm withoutmodifying the power setting. However, if the measured impedance isdifferent from the set threshold, then the controller 724 executes thepre-treatment algorithm by adjusting the power setting by an adjustmentvalue, which may be the same as a percentage difference between themeasured parameter and the set threshold. In embodiments, the adjustmentvalue may be based on a look-up table or calculated according to atransfer function by the controller 724.

With reference to FIG. 10, a further embodiment of a pre-treatmentalgorithm for achieving conductor breakthrough in the non-stick coating400 is shown as a flow chart 1000. Initially, the controller 724 signalsthe power converter 728 to output an RF waveform for a set period oftime, which may be similar to the waveform of the algorithms of the flowcharts 800 and 900. The RF waveform is applied for a period of time,which may be from about 50 msec to about 1 sec, and in embodiments, maybe from about 100 msec to about 200 msec. The controller 724continuously receives measured impedance from sensors of the generator700 and compares the measured impedance to a set impedance that isindicative of achieving conductor breakthrough of the non-stick coating400. The set impedance may be settable by the user or automatically bythe generator 700 based on the type of forceps 10 connected to thegenerator 700. Similarly to the algorithms of the flow charts 800 and900, the measured parameter and threshold may be voltage and/or current.

If the measured impedance drops below the set impedance, then thecontroller 724 proceeds to execute a treatment algorithm such as sealingalgorithms disclosed in U.S. Pat. No. 8,147,485 and U.S. PatentApplication Publication No. 2016/0045248 as incorporated by referenceabove. If the impedance is above the set threshold, then the generator700 continues to apply the RF waveform until set time period expires.

The controller 724 maintains a timer for the application of the RFwaveform and compares the measured time of the timer to the set timeperiod. If the timer has not yet expired, namely, if the measured timeis below the set time period, and the impedance does not drop below theset threshold (or if current and/or voltage does not exceed the setthreshold), the generator 700 continues to apply the RF waveform untilthe set time period expires.

In addition, the controller 724 also increases a power setting of the RFwaveform. In embodiments, the power intensity may be increasedincrementally and periodically. More specifically, the power intensityof the RF waveform may be increased in any suitable increment, such asby about 5% of the initial power setting or discrete power amounts, suchas from about 10 watts to about 40 watts, or in embodiments from about20 watts to about 30 watts. The power setting increments may occurperiodically, with each period being from about 5 msec to about 50 msec,in embodiments from about 10 msec to about 30 msec.

If the set time period expires, without the measured impedance droppingbelow the set threshold or without the measured current and/or voltageexceeding the set threshold, then the pre-treatment algorithm instructsthe generator 700 to issue a retry alert, such as instructing the userto regrasp the tissue with the jaw members 110 and 120.

It will be appreciated that of the above-disclosed and other featuresand functions, or alternatives thereof, may be desirably combined intomany other different systems or applications. Also that variouspresently unforeseen or unanticipated alternatives, modifications,variations or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims. Unless specifically recited in a claim, steps orcomponents of claims should not be implied or imported from thespecification or any other claims as to any particular order, number,position, size, shape, angle, or material.

What is claimed is:
 1. An electrosurgical system comprising: anelectrosurgical instrument including an electrode having a polymericdielectric coating; and an electrosurgical generator including: a powerconverter configured to generate RF energy; a sensor coupled to thepower converter and configured to sense at least one parameter of the RFenergy; and a controller coupled to the sensor and the power converter,the controller configured to: control the power converter to output anRF waveform to achieve conductor breakthrough through the polymericdielectric coating; determine whether the conductor breakthroughoccurred based on the at least one parameter; and execute a treatmentalgorithm based on a determination of the conductor breakthrough.
 2. Theelectrosurgical system according to claim 1, wherein the controller isfurther configured to compare the at least one parameter to a setthreshold indicative of the conductor breakthrough.
 3. Theelectrosurgical system according to claim 2, wherein the controller isfurther configured to control the power converter to output the RFwaveform for a set period of time.
 4. The electrosurgical systemaccording to claim 3, wherein the controller is further configured toexecute the treatment algorithm based on the determination of theconductor breakthrough occurring within the set period of time.
 5. Theelectrosurgical system according to claim 1, wherein the at least oneparameter is measured impedance and the controller is further configuredto compare the measured impedance to a set impedance threshold.
 6. Theelectrosurgical system according to claim 5, wherein the controller isfurther configured to execute the treatment algorithm in response to themeasured impedance being below the set impedance threshold.
 7. Theelectrosurgical system according to claim 6, wherein the controller isfurther configured to adjust a power setting of the treatment algorithmprior to the execution of the treatment algorithm in response to themeasured impedance being above the set impedance threshold.
 8. Theelectrosurgical system according to claim 6, wherein the controller isfurther configured to adjust a power setting of the RF waveform inresponse to the measured impedance being above the set impedancethreshold.
 9. The electrosurgical system according to claim 1, whereinthe at least one parameter is measured voltage and the controller isfurther configured to compare the measured voltage to a set voltagethreshold.
 10. The electrosurgical system according to claim 1, whereinthe at least one parameter is measured current and the controller isfurther configured to compare the measured current to a set currentthreshold.
 11. A method comprising: electrically coupling anelectrosurgical instrument to an electrosurgical generator, theelectrosurgical instrument including an electrode having a polymericdielectric coating; controlling a power converter of the electrosurgicalgenerator to output an RF waveform to achieve conductor breakthroughthrough the polymeric dielectric coating; sensing at least one parameterof the RF waveform at a sensor of the electrosurgical generator;determining at a controller of the electrosurgical generator whether theconductor breakthrough occurred based on the at least one parameter; andexecuting a treatment algorithm at the controller based on adetermination of the conductor breakthrough.
 12. The method according toclaim 11, wherein determining whether the conductor breakthroughoccurred further includes comparing the at least one parameter to a setthreshold indicative of the conductor breakthrough.
 13. The methodaccording to claim 12, further comprising outputting the RF waveform fora set period of time.
 14. The method according to claim 13, wherein thetreatment algorithm is executed based on the determination of theconductor breakthrough occurring within the set period of time.
 15. Themethod according to claim 11, further comprising: measuring impedance;and comparing the measured impedance to a set impedance threshold. 16.The method according to claim 15, further comprising executing thetreatment algorithm in response to the measured impedance being belowthe set impedance threshold.
 17. The method according to claim 16,further comprising adjusting a power setting of the treatment algorithmprior to the execution of the treatment algorithm in response to themeasured impedance being above the set impedance threshold.
 18. Themethod according to claim 16, further comprising adjusting a powersetting of the RF waveform in response to the measured impedance beingabove the set impedance threshold.
 19. The method according to claim 11,further comprising: measuring voltage; and comparing the measuredvoltage to a set voltage threshold.
 20. The method according to claim11, further comprising: measuring current; and comparing the measuredcurrent to a set current threshold.